Follow the headline link to the iFixit teardown page for the Google Pixel 3a. Lots of step-by-step images and details. This is one of the most easy to take apart phones on the market but, that said, it is still an incredibly complex puzzle to put back together.
Take a look if your inner nerd runs that way.
And, if video is more your thing, embedded below is the teardown of the Pixel 3a XL.